package com.yuzhi.fine.number;

/**
 * Created by tiansj on 17/4/14.
 */
public class VersionCompare {

    public static void main(String[] args) {
        try {
            System.out.println(compareVersion("3.8.11", "3.8.8"));
            System.out.println(compareVersion("3.8.1.1", "3.8.8"));
            System.out.println(compareVersion("3.8.8", "3.8.11"));
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public static int compareVersion(String version1, String version2) throws Exception {
        if (version1 == null || version2 == null) {
            throw new Exception("compareVersion error:illegal params.");
        }
        String[] versionArray1 = version1.split("\\.");//注意此处为正则匹配，不能用"."；
        String[] versionArray2 = version2.split("\\.");
        int idx = 0;
        int minLength = Math.min(versionArray1.length, versionArray2.length);//取最小长度值
        int diff = 0;
        while (idx < minLength
                && (diff = versionArray1[idx].length() - versionArray2[idx].length()) == 0//先比较长度
                && (diff = versionArray1[idx].compareTo(versionArray2[idx])) == 0) {//再比较字符
            ++idx;
        }
        //如果已经分出大小，则直接返回，如果未分出大小，则再比较位数，有子版本的为大；
        diff = (diff != 0) ? diff : versionArray1.length - versionArray2.length;
        return diff;
    }
}
